Yanmar 2GM20F

[smurphny]

The rebuild parts are not too expensive. If, as Minnewaska has said, you get bearings fitted and valves redone in a shop, you should be able to save some bucks. I would remove the head first and check for how much wear is on the cylinder walls. Then plastigauge a couple of journals. Get an idea of general wear. If you see a big ridge or heavy scoring, it may be better to just order a brand new short block and reuse everything else.